/**
 * Copyright (c) 2006-2015, JGraph Ltd
 * Copyright (c) 2006-2015, Gaudenz Alder
 */
/**
 * Class: mxCellHighlight
 *
 * A helper class to highlight cells. Here is an example for a given cell.
 *
 * (code)
 * var highlight = new mxCellHighlight(graph, '#ff0000', 2);
 * highlight.highlight(graph.view.getState(cell)));
 * (end)
 *
 * Constructor: mxCellHighlight
 *
 * Constructs a cell highlight.
 */
function mxCellHighlight(graph, highlightColor, strokeWidth, dashed) {
    if (graph != null) {
        this.graph = graph;
        this.highlightColor = (highlightColor != null) ? highlightColor : mxConstants.DEFAULT_VALID_COLOR;
        this.strokeWidth = (strokeWidth != null) ? strokeWidth : mxConstants.HIGHLIGHT_STROKEWIDTH;
        this.dashed = (dashed != null) ? dashed : false;
        this.opacity = mxConstants.HIGHLIGHT_OPACITY;

        // Updates the marker if the graph changes
        this.repaintHandler = mxUtils.bind(this, function () {
            // Updates reference to state
            if (this.state != null) {
                var tmp = this.graph.view.getState(this.state.cell);

                if (tmp == null) {
                    this.hide();
                }
                else {
                    this.state = tmp;
                    this.repaint();
                }
            }
        });

        this.graph.getView().addListener(mxEvent.SCALE, this.repaintHandler);
        this.graph.getView().addListener(mxEvent.TRANSLATE, this.repaintHandler);
        this.graph.getView().addListener(mxEvent.SCALE_AND_TRANSLATE, this.repaintHandler);
        this.graph.getModel().addListener(mxEvent.CHANGE, this.repaintHandler);

        // Hides the marker if the current root changes
        this.resetHandler = mxUtils.bind(this, function () {
            this.hide();
        });

        this.graph.getView().addListener(mxEvent.DOWN, this.resetHandler);
        this.graph.getView().addListener(mxEvent.UP, this.resetHandler);
    }
};

/**
 * Variable: keepOnTop
 *
 * Specifies if the highlights should appear on top of everything
 * else in the overlay pane. Default is false.
 */
mxCellHighlight.prototype.keepOnTop = false;

/**
 * Variable: graph
 *
 * Reference to the enclosing <mxGraph>.
 */
mxCellHighlight.prototype.graph = null;

/**
 * Variable: state
 *
 * Reference to the <mxCellState>.
 */
mxCellHighlight.prototype.state = null;

/**
 * Variable: spacing
 *
 * Specifies the spacing between the highlight for vertices and the vertex.
 * Default is 2.
 */
mxCellHighlight.prototype.spacing = 2;

/**
 * Variable: resetHandler
 *
 * Holds the handler that automatically invokes reset if the highlight
 * should be hidden.
 */
mxCellHighlight.prototype.resetHandler = null;

/**
 * Function: setHighlightColor
 *
 * Sets the color of the rectangle used to highlight drop targets.
 *
 * Parameters:
 *
 * color - String that represents the new highlight color.
 */
mxCellHighlight.prototype.setHighlightColor = function (color) {
    this.highlightColor = color;

    if (this.shape != null) {
        this.shape.stroke = color;
    }
};

/**
 * Function: drawHighlight
 *
 * Creates and returns the highlight shape for the given state.
 */
mxCellHighlight.prototype.drawHighlight = function () {
    this.shape = this.createShape();
    this.repaint();

    if (!this.keepOnTop && this.shape.node.parentNode.firstChild != this.shape.node) {
        this.shape.node.parentNode.insertBefore(this.shape.node, this.shape.node.parentNode.firstChild);
    }
};

/**
 * Function: createShape
 *
 * Creates and returns the highlight shape for the given state.
 */
mxCellHighlight.prototype.createShape = function () {
    var shape = this.graph.cellRenderer.createShape(this.state);

    shape.svgStrokeTolerance = this.graph.tolerance;
    shape.points = this.state.absolutePoints;
    shape.apply(this.state);
    shape.stroke = this.highlightColor;
    shape.opacity = this.opacity;
    shape.isDashed = this.dashed;
    shape.isShadow = false;

    shape.dialect = (this.graph.dialect != mxConstants.DIALECT_SVG) ? mxConstants.DIALECT_VML : mxConstants.DIALECT_SVG;
    shape.init(this.graph.getView().getOverlayPane());
    mxEvent.redirectMouseEvents(shape.node, this.graph, this.state);

    if (this.graph.dialect != mxConstants.DIALECT_SVG) {
        shape.pointerEvents = false;
    }
    else {
        shape.svgPointerEvents = 'stroke';
    }

    return shape;
};

/**
 * Function: getStrokeWidth
 *
 * Returns the stroke width.
 */
mxCellHighlight.prototype.getStrokeWidth = function (state) {
    return this.strokeWidth;
};

/**
 * Function: repaint
 *
 * Updates the highlight after a change of the model or view.
 */
mxCellHighlight.prototype.repaint = function () {
    if (this.state != null && this.shape != null) {
        this.shape.scale = this.state.view.scale;

        if (this.graph.model.isEdge(this.state.cell)) {
            this.shape.strokewidth = this.getStrokeWidth();
            this.shape.points = this.state.absolutePoints;
            this.shape.outline = false;
        }
        else {
            this.shape.bounds = new mxRectangle(this.state.x - this.spacing, this.state.y - this.spacing,
                this.state.width + 2 * this.spacing, this.state.height + 2 * this.spacing);
            this.shape.rotation = Number(this.state.style[mxConstants.STYLE_ROTATION] || '0');
            this.shape.strokewidth = this.getStrokeWidth() / this.state.view.scale;
            this.shape.outline = true;
        }

        // Uses cursor from shape in highlight
        if (this.state.shape != null) {
            this.shape.setCursor(this.state.shape.getCursor());
        }

        // Workaround for event transparency in VML with transparent color
        // is to use a non-transparent color with near zero opacity
        if (mxClient.IS_QUIRKS || document.documentMode == 8) {
            if (this.shape.stroke == 'transparent') {
                // KNOWN: Quirks mode does not seem to catch events if
                // we do not force an update of the DOM via a change such
                // as mxLog.debug. Since IE6 is EOL we do not add a fix.
                this.shape.stroke = 'white';
                this.shape.opacity = 1;
            }
            else {
                this.shape.opacity = this.opacity;
            }
        }

        this.shape.redraw();
    }
};

/**
 * Function: hide
 *
 * Resets the state of the cell marker.
 */
mxCellHighlight.prototype.hide = function () {
    this.highlight(null);
};

/**
 * Function: mark
 *
 * Marks the <markedState> and fires a <mark> event.
 */
mxCellHighlight.prototype.highlight = function (state) {
    if (this.state != state) {
        if (this.shape != null) {
            this.shape.destroy();
            this.shape = null;
        }

        this.state = state;

        if (this.state != null) {
            this.drawHighlight();
        }
    }
};

/**
 * Function: isHighlightAt
 *
 * Returns true if this highlight is at the given position.
 */
mxCellHighlight.prototype.isHighlightAt = function (x, y) {
    var hit = false;

    // Quirks mode is currently not supported as it used a different coordinate system
    if (this.shape != null && document.elementFromPoint != null && !mxClient.IS_QUIRKS) {
        var elt = document.elementFromPoint(x, y);

        while (elt != null) {
            if (elt == this.shape.node) {
                hit = true;
                break;
            }

            elt = elt.parentNode;
        }
    }

    return hit;
};

/**
 * Function: destroy
 *
 * Destroys the handler and all its resources and DOM nodes.
 */
mxCellHighlight.prototype.destroy = function () {
    this.graph.getView().removeListener(this.resetHandler);
    this.graph.getView().removeListener(this.repaintHandler);
    this.graph.getModel().removeListener(this.repaintHandler);

    if (this.shape != null) {
        this.shape.destroy();
        this.shape = null;
    }
};